// const reg = /^[0-9a-zA-Z]{3,6}$/g;
// let s1 = "12456";
// console.log(reg.test(s1));//true
// let s2="q23456";
// console.log(reg.test(s2));//true



// const reg= /热干面|牛肉面|豆皮/g;
// let str ="热干面是我家的，不是拥有牛肉面的襄阳。。。";
// const re =str.replace(reg,"**");
// console.log(re);


// const reg = /[0-9]+/g;
// let str = "1fdd234gdsgd56789";
// console.log(str.match(reg));


// 把一组数字,使用千位分隔符分割

const reg = /(\d)(?=(\d{3})+$)/g;
let str = "1234567890";
const re = str.replace(reg,"$1,");
console.log(re);